To protect your account, WhatsApp will send you a push notification when someone tries to register a WhatsApp account with your phone number. To keep your account safe, don't share your verification code with others.
When you receive this notification, it means that someone has entered your phone number and requested the registration code. This often happens if another user mistyped your number when trying to enter their own number to register, and can also happen when someone attempts to take over your account.
You should never share your WhatsApp verification code with others. If someone is trying to take over your account, they need the SMS verification code sent to your phone number to do so. Without this code, any user attempting to verify your number can’t complete the verification process and use your phone number on WhatsApp. This means you remain in control of your WhatsApp account.